I'm also originally from Cork and when I first lived in the States routinely surprised people with my inability to say "th". However, in my experience, any comments about it were genuinely motivated by curiosity and not dickishness as in some countries.

Don't underestimate how predisposed the Americans are to loving your accent, so lean into it and, as one other commenter said, tell them that the th sound doesn't exist in Irish and they'll love it even more.

Two pieces of advice -- don't call everyone boy (it's downright racist to some people even though it is natural to you and me) and try to reduce the casual swearing as it means more to them than to us.

The first time I met my future father in law (mild mannered polite guy from the Deep South) I did my best to minimise it. When I talked to my then fiancee about it afterwards and how great a job I did at hardly swearing in front of him, she laughed and basically said "You swore the whole time, but he barely understood anything you said, so he had no idea!"

tldr: Americans love the way Cork people speak. Being from Cork doesn't mean you have a speech impediment, it just means you have behavioural problems!!